The present invention relates to an electric motor, and more particularly to a stator for a small-sized electric motor, and provides an improved stator and a method of producing the stator.
A conventional stator for use in an electric motor of a small size is disclosed in Japanese Patent Publication No. 52-79207 (unexamined), published Jul. 4, 1977. The conventional stator is produced by the steps of placing core plates having a ring-shaped link unit around a central bore for rotatably receiving a rotor and teeth interlinked with the link unit, laying the core plates to form a stator core, winding stator wires on the teeth from an outer periphery of the stator core, and forcing the stator core into a ring core.
In the conventional stator of the Japanese publication, the ring-shaped link unit is used to hold the teeth in position, so that the link unit can prevent the teeth from being separated from the link unit. Thus, the efficiency of assembling the stator is improved at the same time.
One of the problems inherent in the conventional stator resides in a leakage of magnetic flux. In other words, since the ring-shaped link unit and the teeth are unitarily press-formed of the same material, the magnetic flux produced in the teeth tends to leak through the ring-shaped link unit, and the ring shaped link unit develops into a magnetic "bridge", and thus the operational efficiency of the motor is lowered.